Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context by listing the output statistics and histogram, and by noting it works across many data providers. It does not disclose details like what happens for missing data or how the histogram is rendered, but with strong annotations this is acceptable.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences with zero filler. The first sentence front-loads the core purpose, the second gives immediate usage guidance, and the third scopes data sources. Every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only descriptive tool, the description lists the key output statistics well. However, with no output schema, it does not explain how the result object is structured or how the optional time parameter affects computation. This is serviceable but leaves a notable hole for an agent deciding whether to pass time.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must carry the parameter semantics. It clarifies that indicator refers to verified autario indicators from named sources and that the call targets a single entity, but it leaves the optional 'time' parameter entirely unexplained and does not specify acceptable formats for entity or indicator. This is a meaningful gap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Summary statistics for a single indicator+entity', then enumerates the exact statistics (n, mean, median, std, min/max, quartiles, skew, histogram). This clearly distinguishes it from sibling tools like compare_entities or correlate, which involve multiple entities or indicators.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly instructs 'Use FIRST before running any test', giving a clear trigger condition and context (knowing sample size, completeness, distribution shape). It also scopes the tool to 'any verified autario indicator'. However, it does not name alternative tools or explicitly state when not to use it, so it stops short of full exclusion guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.